December. 1896. THE STUDY OF THE GIBBON. 373 



siderable amount of attention, those of the limbs from Hepburn (45), 

 Kohlbriigge (313), and Ruge (316), while the two anatomists named 

 last, Jhering (143), and Utschneider (209) have described the arrange- 

 ment of the trunk plexuses. From the above list it will be noticed 

 that there is a complete absence of any inquiry into the more minute 

 anatomy of the nervous system. 



The Muscular System. — Kohlbriigge (313) and Deniker (17) 

 have given very complete descriptions of the muscles — in fact, the 

 most complete accounts we have of the muscular system of any of 

 the anthropoids. Bischoff (293) also investigated this system in detail, 

 while Hepburn's (45) account refers to the muscles of the limbs 

 only. The muscles of the face and of the trunk have been very 

 exactly described and figured by Ruge (70, 190, 316). Other facts 

 may be gleaned from the dissections of Sandifort (271) and Vrolik 

 (210). There are a number of special papers, mostly dealing with 

 muscles of the toes or fingers, by Bischoff (100), St. John Brooks 

 (106, 107), Schulze (318), Testut (321^), and Keith (148, 311^). 



The Joints and Ligaments. — The ligamentous structures have 

 been described, but not very fully, by Deniker (17), Kohlbrugge (313), 

 and Keith (250). 



The Skull. — Most of the literature on the skull of the gibbon is of a 

 general and unsatisfactory nature. No attempt has been made, upon 

 a sufficiency of material, to determine either the specific or generic 

 cranial characters. It is true that Giebel (305) and Anderson (291) 

 pointed out certain features of the skull which they thought 

 characteristic of certain species, but they had too few skulls at hand 

 to draw conclusions with any degree of security. In a collection of 

 gibbon skulls, the only one which is distinguished from the rest with 

 facility is that of the Siamang (H. syndactylus ) ; all the others, with 

 perhaps the exception of that of H. agilis, being recognisable from 

 each other only by their labels. It is possible that an examination of 

 a much larger collection than thirty-five skulls, which is the number 

 I had for study, might lead to more positive conclusions, but as yet 

 there is not material enough collected for such an investigation. 

 Descriptions of the cranial characters may be found in Duvernoy (22), 

 Bischoff (293), Fry (302), Schlegel (193), Huxley (49^), and in most 

 text-books or general works on mammalian osteology. There are 

 some papers dealing with special features, such as those of Albrecht 

 (290) and Morselli (169) with the vermian fossa ; of Gegenbaur (303) 

 with the lachrymal bone ; of Hamy (35) with the anterior nasal spine ; 

 of Regnault (182) with the sutures surrounding that bone; of Seydel 

 (278) with the nasal cavities; of Keith (31 1«) with the temporal 

 ridges ; and of Waldeyer (211) with the posterior palatal spine. 



The Skeleton. — Descriptions of the skeletal characters are given 

 by Blainville (223), Duvernoy (22), Bischoff (293), Meyer (58), Mivart 

 (61, 6ia), Fry (302), Schlegel (193), and Vrolik (210). For observa- 

 tions on the bones of the hand and foot, one may consult Lucae (54), 



